1. Field of the Invention
The present invention relates to a heating resistance element component (thermal head) which is used in a thermal printer typically mounted onto a compact information equipment terminal such as a compact handy terminal, and which is used for performing printing on a thermal recording medium through selective driving of a plurality of heating elements based on print data.
2. Description of the Related Art
Recently, thermal printers are widely used in compact information equipment terminals. The compact information equipment terminals are driven by a battery, which leads to strong demands for electric power saving of the thermal printers. Accordingly, there have been growing demands for thermal heads having high heating efficiency.
As to increasing efficiency of the thermal head, there is a method of forming a heat insulating layer as a lower layer of a heating resistor (for example, see JP 2004-34601 A). Among an amount of heat generated in the heating resistor, an amount of upper-transferred heat which is transferred to a wear-resistant layer formed above the heating resistor becomes larger than an amount of lower-transferred heat which is transferred to an insulating substrate under the heating resistor, and thus energy efficiency required during the printing can be sufficiently obtained.
However, in the thermal head disclosed in JP 2004-34601 A, heat generated in a heating element passes through a reinforcement layer, an undercoat, and a heat storage layer at a connecting portion to be diffused to an entire substrate, which leads to a decrease in heating efficiency.
Also in the thermal head disclosed in JP 2004-34601 A, the reinforcement layer which may absorb an external load which acts on an enclosed cavity is provided between the heating element and the enclosed cavity. However, the reinforcement layer has a bending portion, which makes it difficult to provide the reinforcement layer with sufficient strength to absorb the external load.